Evaluation of carbon-11 labeled 5-(1-methyl-1H-pyrazol-4-yl)-N-(2-methyl-5-(3-(trifluoromethyl)benzamido)phenyl)nicotinamide as PET tracer for imaging of CSF-1R expression in the brain.
Bioorg Med Chem
; 42: 116245, 2021 07 15.
Article
en En
| MEDLINE
| ID: mdl-34119698
ABSTRACT
Pharmacological targeting of tumor associated macrophages and microglia in the tumor microenvironment is a novel therapeutic strategy in the treatment of glioblastoma multiforme. As such, the colony stimulating factor-1 receptor (CSF-1R) has been identified as a druggable target. However, no validated companion diagnostic marker for these therapies exists to date. Towards development of a CSF-1R PET tracer, a set of six compounds based on recently reported CSF-1R inhibitor 5-(1-methyl-1H-pyrazol-4-yl)-N-(2-methyl-5-(3-(trifluoromethyl)benzamido)phenyl)nicotinamide (Compound 5) was designed, synthesized and evaluated in vitro for potency and selectivity. The highest affinity for CSF-1R was found for compound 5 (IC50 2.7 nM). Subsequent radiosynthesis of [11C]5 was achieved in 2.0 ± 0.2% yield (decay corrected to start of synthesis) by carbon-11 carbon monoxide aminocarbonylation in 40 min after end of bombardment. In vitro autoradiography with [11C]5 on rat brain sections demonstrated high specific binding, but also strong off-target binding. Ex vivo, only intact tracer was observed in blood plasma at 90 min post injection in healthy rats. PET scanning results demonstrated negligible brain uptake under baseline conditions and this brain uptake did not increase by blocking of efflux transporters using Tariquidar. To conclude, [11C]5 was successfully synthesized and evaluated in healthy rats. However, the inability of [11C]5 to cross the blood-brain-barrier excludes its use for imaging of CSF-1R expression in the brain.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Encéfalo
/
Receptor de Factor Estimulante de Colonias de Macrófagos
/
Tomografía de Emisión de Positrones
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Bioorg Med Chem
Asunto de la revista:
BIOQUIMICA
/
QUIMICA
Año:
2021
Tipo del documento:
Article
País de afiliación:
Países Bajos